Dual Channel RAM, how does that really work?

[Anonymous Joe]

How does dual channel ram actually work. I know it makes up a 128-bit
channel when you use two dimms placed in the correct locale, but what does
that really mean to the two dimms? Is it similar to RAID for hard drives,
so that if you store, for example, a 1mb exe file into ram as do all
programs, does 512kb get stored to dimm 0, and 512k to dimm 2 (just because
in dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do as
well, atleast on a 4-dimm board, like mine).

[daytripper]

On Tue, 20 Apr 2004 02:28:23 GMT, "Anonymous Joe" <anonymousjoe@net.net>
wrote:
How does dual channel ram actually work. I know it makes up a 128-bitchannel when you use two dimms placed in the correct locale, but what doesthat really mean to the two dimms? Is it similar to RAID for hard drives,so that if you store, for example, a 1mb exe file into ram as do allprograms, does 512kb get stored to dimm 0, and 512k to dimm 2 (just becausein dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do aswell, atleast on a 4-dimm board, like mine).

If a disk paradigm you must have, think of the pair of dimms as a 2-way stripe
set...

hth ;-)

/daytripper

[KR Williams]

In article <s35980d9e6oje8bp85tjkvip3ikhdokrpk@4ax.com>,
day_trippr@REMOVEyahoo.com says... On Tue, 20 Apr 2004 02:28:23 GMT, "Anonymous Joe" <anonymousjoe@net.net> wrote:How does dual channel ram actually work. I know it makes up a 128-bitchannel when you use two dimms placed in the correct locale, but what doesthat really mean to the two dimms? Is it similar to RAID for hard drives,so that if you store, for example, a 1mb exe file into ram as do allprograms, does 512kb get stored to dimm 0, and 512k to dimm 2 (just becausein dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do aswell, atleast on a 4-dimm board, like mine). If a disk paradigm you must have, think of the pair of dimms as a 2-way stripe set...

With a 16-byte stripe?

--
Keith

[daytripper]

On Fri, 23 Apr 2004 21:40:22 -0400, KR Williams <krw@att.biz> wrote:
In article <s35980d9e6oje8bp85tjkvip3ikhdokrpk@4ax.com>,day_trippr@REMOVEyahoo.com says... On Tue, 20 Apr 2004 02:28:23 GMT, "Anonymous Joe" <anonymousjoe@net.net> wrote:How does dual channel ram actually work. I know it makes up a 128-bitchannel when you use two dimms placed in the correct locale, but what doesthat really mean to the two dimms? Is it similar to RAID for hard drives,so that if you store, for example, a 1mb exe file into ram as do allprograms, does 512kb get stored to dimm 0, and 512k to dimm 2 (just becausein dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do aswell, atleast on a 4-dimm board, like mine). If a disk paradigm you must have, think of the pair of dimms as a 2-way stripe set...With a 16-byte stripe?

That'd depend on the burst length (which is usually figured based on cache
line size) so a cache line of 32 bytes with a "dual channel" memory, a 16 byte
stripe would be correct...

/daytripper

[KR Williams]

In article <rjrl80hv1hbvrqp8k6vgfdd6lt4bb8tbuf@4ax.com>,
day_trippr@REMOVEyahoo.com says... On Fri, 23 Apr 2004 21:40:22 -0400, KR Williams <krw@att.biz> wrote:In article <s35980d9e6oje8bp85tjkvip3ikhdokrpk@4ax.com>,day_trippr@REMOVEyahoo.com says... On Tue, 20 Apr 2004 02:28:23 GMT, "Anonymous Joe" <anonymousjoe@net.net> wrote: >How does dual channel ram actually work. I know it makes up a 128-bit >channel when you use two dimms placed in the correct locale, but what does >that really mean to the two dimms? Is it similar to RAID for hard drives, >so that if you store, for example, a 1mb exe file into ram as do all >programs, does 512kb get stored to dimm 0, and 512k to dimm 2 (just because >in dual channel, usually dimm0 & 2 make up a chanel, and dimm 1 & 3 do as >well, atleast on a 4-dimm board, like mine). If a disk paradigm you must have, think of the pair of dimms as a 2-way stripe set...With a 16-byte stripe? That'd depend on the burst length (which is usually figured based on cache line size) so a cache line of 32 bytes with a "dual channel" memory, a 16 byte stripe would be correct...

Actually I forgot the --> ;-)

--
Keith